In U.S. Pat. Nos. 3,161,223, 3,481,174, 3,482,427, 3,559,444, 3,817,075 and 3,872,755, there are disclosed sheet bending brakes for bending metal or plastic sheets as are used in siding on homes and buildings.
In my U.S. application Ser. No. 141,427 filed Apr. 18, 1980 there is disclosed a sheet metal brake comprising a frame having a fixed jaw and a movable jaw and an anvil member adjustably secured to the movable jaw. The movable jaw has a clamping surface movable between workpiece clamping and non-clamping positions relative to the clamping surface on the fixed jaw. A bending member is hingedly connected to the fixed jaw. The movable jaw is releasably locked in workpiece clamping position by a structure that includes an oval shaped spring member having opposed ends and opposed walls. The member is pivoted at one end to the movable jaw and at the other end to a handle for manipulating the jaw.
In such sheet metal brakes it is desirable to provide for bending sheet material of various thicknesses as well as the ability to accommodate manufacturing variations or tolerances in the sheet material.
Among the objects of the present invention are to provide a sheet bending brake of the aforementioned type wherein the sheet bending brake will accommodate manufacturing variations or tolerances in the sheet material without adjustment and will also be adjustable to accommodate variations in thickness of the sheet material and to facilitate locking and unlocking of the sheet material.
In accordance with the invention, a plurality of extensible links are provided between a clamping handle and the movable jaw. Each link includes an axially resilient portion which will accommodate manufacturing variations or tolerances in the sheet material. The link is also axially adjustable in length to accommodate the sheet bending brake to workpiece of differing and varying thicknesses and to facilitate locking and unlocking of the sheet material.